U.S. Route 29 (US 29) is a north–south United States Numbered Highway that runs for 1,043.3 miles (1,679.0 km) from Pensacola, Florida, to the western suburbs of Baltimore, Maryland.

Crossing Sligo Creek Park, the highway intersects the Sligo Creek Parkway just to the south of the Capital Beltway (Interstate 495, or I-495); a partial cloverleaf interchange between the highways prevents direct access from US 29 south to I-495 east and I-495 west to US 29 north.

After crossing the Northwest Branch Park, the route is now known as Columbia Pike and remains a six-lane divided expressway.

Running northwest of Fairland Regional Park, US 29 reaches its first major freeway segment at Burtonsville, bypassing a former, heavily curved at-grade expressway portion through the community.

The 0.92-mile (1.48 km) bypassed section of the old road is officially designated US 29A with street signs that say "Old Columbia Pike", which previously ended at MD 198.

The route crosses Rocky Gorge Reservoir and enters Howard County just beyond the northern end of the bypass.

It intersects Old Columbia Road just beyond the reservoir and then upgrades into a six-lane grade-separated almost-freeway within its interchange with MD 216 at Scaggsville.

Next, US 29 encounters MD 32 at a symmetrical cloverleaf; for an extended period, this interchange marked the southern end of US 29's grade separation, with the entire route south of there being an at-grade expressway.

The eight-lane segment narrows to six lanes again as it encounters the historic northern end of the US 29 expressway at US 40 within Ellicott City.

Beyond US 40, US 29 interchanges with I-70 at a modified directional cloverleaf and finally terminates at an at-grade intersection with MD 99 near Mount Hebron.

[4] In 1835, Columbia Pike surrendered its Montgomery and Anne Arundel (Howard) county roads and bridges to the State of Maryland.

[2] The diversion of the route necessitated the construction of a divided highway between the site of US 29's current interchange with MD 650 in White Oak and an intersection with MD 198 in Burtonsville, and a two-lane highway between Burtonsville, across the Patuxent River at the site of future Rocky Gorge Reservoir, through Scaggsville and Columbia (then a small village east of today's US 29/MD 108 interchange) to a point south of Ellicott City, where the new route merged with the original route near the site of the US 29/MD 103 interchange and continued as normal.

By the early 1970s, with the completion of new Columbia Pike, a four-lane divided at-grade highway, between Burtonsville and US 40, US 29 had assumed its current shape.

[12] In 1968, the terminus of US 29 was diverted away from Baltimore; it was retracted to US 40 in Ellicott City and then moved north two miles (3.2 km) to MD 99, and an interchange similar to the one in place between US 29 and US 40 was built to connect the route with I-70 (then designated I-70N).

Immediately south of Briggs Chaney Road, construction commenced on a new interchange with MD 200 (Intercounty Connector) in 2008.

Future plans under study would eliminate all traffic lights between Rivers Edge Road and Stewart Lane.